Improvement in crucibles for melting iron, steel



UNITED TATES AEN WILLIAM F. DUNBARR, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO HIM- SELF AND SAMUEL M. KIER.

IMPROVEMENT IN CRUClBLES FOR MELTING IRON, STEEL, 8w.

Specification forming part of Letters Patent No. 122,585, dated January 9, 1872.

To all whom it may concern:

Be it known that I, WILLIAM F. DUNBARR, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered a new and useful Compound for Glazing or Coating Grucibles, of whichthe following is a specification:

This invention has for its object to produce a cheap and easily-obtained compound for glaz ing or coating the outer surfaces of crucibles, so as to render the same impenetrable to the action of fire, whereby what is termed cutting and the burning out of carbon and plumbago is prevented.

In carrying out my invention I employ and combine several well-known ingredients in or about the following proportions, namely: Glass, say about ten (10) parts; common yellow clay, about thirty (30) parts; old crucibles, about ten (10) parts; old fire-bricks, about twenty (20) parts 5 burnt or parting-sand, about thirty (30) parts.

These several substances, in or about the proportions specilied, are crushed or ground in a suitable mill or other machine, or in any suit able manner, and all are thoroughly mixed together, when a sufficient quantity of water or other liquid is added to render the mass plastic or to a thick paste. When the compound is thus prepared it is ready for use that is, for glazing, coating, or painting the outer surfaces of crucibles which said compound may be applied by means of brushes or by any other desired means. This compound, it will be found, melts at a low heat, and, owing to its cohesive quality and smooth glazed surface, all burnings out of carbon and plumbago contained in said crucibles isprevented, and all cutting by the action of the fire is avoided.

All the ingredients employed by me are most easily obtained, and the compound, when prepared and applied as aforesaid, will be found to produce most beneficial and economical results.

In applying this compound upon the outside surface of old or new crucibles it is found, by actual experiment, to coat or paint the crucibles with one or more coats, according to the metal desired to be melted or treated; thus,

for new crucibles from one to three coatings should be applied before they are used, and after they have run one dayor about three heats, then apply another coating. Grucibles for melting or treating iron should be painted or coated before each heat. The crucible may be dipped into the compound for coating it.

The special feature of my invention is that the compound melts at a low heat and quite rapidly; and when applied to crucibles for melting copper, brass, iron, steel, 850., it protects the outside surface of the crucibles, so that the same resists the cutting action of fire and prevents the deterioration of the carbon and plumbago, as the said surface is rendered smooth and of a glassy or glazed surface.

I am aware of the patent of W. F. Sherman, reissued July 6, 1869, for coating crucibles with a compound of plumbago and other refractory substances; such I do not claim; but

What I claim is-- A compound composed of the ingredients herein specified, or their equivalents, mixed together in or about the proportions named, for coating or glazing the outside surface of crucibles.

Witnesses:

JAMES MOONEY, EDWARD T. Arwoon. I (20) W. F. DUNBARR. 

